Physics

Biography

Biography: Alessandra Toncelli

Abstract

The mid-infrared region (MID-IR) is usually considered spanning from 3 to 8 μm wavelength. This is an extremely useful
region for many applications because roto-vibrational transitions of molecules lie in this region. In fact, possible applications
comprise material analysis, quality control, dynamic measurements, environmental and medical monitoring applications, forensic
testing, analysis of art objects, etc. Historically, laser sources in this region were bulky and did not permit the development of
wide-spread applications. The situation dramatically changed in the last decades with the advent of compact coherent sources
like quantum cascade lasers, which, unfortunately, possess intrinsic limitations as for output peak power and beam quality.
Moreover, most quantum cascade lasers must be operated at cryogenic temperature, although room temperature operation is
possible with strong performance limitations. A completely different approach for MID-IR quantum light generation is the use of
doped insulating crystals as active media. Transition metals like Cr2+ and Fe+2 have already been used as dopant agents for broadly
tunable pulsed emission, but the use of rare earths can widen the emission wavelength regions available and permit continuous
wave (CW) emission with excellent beam quality. Another, more exotic, possibility is the achievement of polariton lasing in
semiconductor heterostructures. A brief review of the state of the art and recent developments in this field will be given.